Cerebral and systemic physiological effects of wearing face masks in young adults.

The COVID-19 pandemic led to widespread mandates requiring the wearing of face masks, which led to debates on their benefits and possible adverse effects. To that end, the physiological effects at the systemic and at the brain level are of interest. We have investigated the effect of commonly available face masks (FFP2 and surgical) on cerebral hemodynamics and oxygenation, particularly microvascular cerebral blood flow (CBF) and blood/tissue oxygen saturation (StO2), measured by transcranial hybrid near-infrared spectroscopies and on systemic physiology in 13 healthy adults (ages: 23 to 33 y). The results indicate small but significant changes in cerebral hemodynamics while wearing a mask. However, these changes are comparable to those of daily life activities. This platform and the protocol provides the basis for large or targeted studies of the effects of mask wearing in different populations and while performing critical tasks.

Study of the effect of anti-rhGAA antibodies at low and intermediate titers in late onset Pompe patients treated with ERT.

Late onset Pompe disease (LOPD) is a genetic disorder characterized by slowly progressive skeletal and respiratory muscle weakness. Symptomatic patients are treated with enzyme replacement therapy (ERT) with alglucosidase alpha (rhGAA). Although most of ERT treated patients develop antibodies against rhGAA, their influence on clinical progression is not completely known. We studied the impact of anti-rhGAA antibodies on clinical progression of 25 ERT treated patients. We evaluated patients at visit 0 and, after 1 year, at visit 1. We performed several muscle function tests, conventional spirometry and quantitative muscle MRI (qMRI) using 3-point Dixon analysis of thigh muscles at both visits. We also obtained serum samples at both visits and anti-rhGAA antibodies were quantified using ELISA. Antibody titers higher than 1:200 were identified in 18 patients (72%) of our cohort. Seven patients (28%) did not develop antibodies (0 to <1:200), 17 patients (68%) developed low to intermediate titers (1:200 to <1:31,200) and 1 patient (4%) developed high titers (>1:31,200). We analyzed the effect of low and intermediate antibody titers in clinical and radiological progression. There were no differences between the results of muscle function tests, spirometry or fat fraction analyzed using qMRI between patients with and without antibodies groups at baseline. Moreover, antibody titers did not influence muscle function test, spirometry results or qMRI results at year 1 visit. Most of the LOPD patients developed antibodies against ERT that persisted over time at low or intermediate levels. However, antibodies at these low and intermediate titers might not influence clinical response to the drug.

Anthropometrical phenotypes are important when explaining obstructive sleep apnea in female bariatric cohorts.

Central obesity is the main risk factor for obstructive sleep apnea (OSA). Whether there exists a central-obesity anthropometric that better explains apnea-hypopnea index (AHI) variability in the general population and in sleep cohorts is unknown, and this is even less explored among increasing grades of obesity. The objective of the study is to investigate whether there is an anthropometric that better explains AHI variability in a sample of morbidly obese women awaiting bariatric surgery (BS). A prospective multicentre cross-sectional study was conducted in consecutive women before BS. Demographic and anthropometric characteristics included age, body mass index (BMI), neck circumference (NC), waist circumference (WC), hip circumference (HC) and waist-to-hip ratio (WHR). OSA was diagnosed by polysomnography. The capacity of anthropometrics to explain AHI variance was investigated using regression linear models. A total of 115 women were evaluated: age, 44 ± 10 years; BMI, 46 ± 5 kg/m2 ; AHI, 35 ± 26 events/hr. AHI was associated with all anthropometrics except weight, height and HC. The best univariate predictor was WHR, which accounted for 15% of AHI variance. The simplest model (age + BMI) accounted for 9%, which increased to 20% when applying more complex measurements (age + BMI + NC + WC + HC). The explanatory capacity did not change significantly when applying a simpler model (age + WHR + NC, 19%). In this female morbidly obese cohort, anthropometrics explained one-fifth of AHI variability. WHR is the best univariate parameter and models including waist and neck data provide more information than BMI when explaining AHI variability. Thus, even in young women with extreme obesity, OSA seems to be linked to a specific central-obesity phenotype rather than to a whole-obesity pattern.

[Obstructive sleep apnea-hypopnea and stroke]. / Síndrome de apneas-hipopneas obstructivas del sueño y accidente cerebrovascular.

Stroke, one of the main causes of disability and death worldwide, is frequently associated to the obstructive sleep apnea-hypopnea syndrome. This sleep disorder has been demonstrated to be an independent risk factor for stroke, and therefore its investigation and treatment has been recommended for patients with stroke. Mechanisms relating these two clinical disorders include: oxidative stress, cerebral blood flow alterations, autonomic dysfunction, and hypercoagulability, as well as patent foramen ovale, blood pressure, and heart rhythm disorders. Increasing amount of evidence supports continuous airway positive pressure therapy in patients with stroke, but further randomized clinical trials are needed to obtain solid conclusions. This work reviews the literature on epidemiology, pathophysiology, clinical assessment, and treatment of apnea-hypopnea syndrome in patients with stroke.

A randomized controlled trial: branched-chain amino acid levels and glucose metabolism in patients with obesity and sleep apnea.

There is evidence that changes in branched-chain amino acid (BCAA) levels may correlate with the efficacy of therapeutic interventions for affecting improvement in metabolic control. The objective of this study was to evaluate whether serum concentrations of BCAAs (leucine, isoleucine, valine) could mediate in insulin sensitivity and glucose tolerance after continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). A prospective randomized controlled trial of OSA patients with morbid obesity was conducted. Eighty patients were randomized into two groups: 38 received conservative treatment and 42 received CPAP treatment for 12 weeks. Plasma levels of BCAA, glucose tolerance and insulin resistance were evaluated at baseline and after treatment. After treatment, significant decreases of leucine levels were observed in both groups when compared with baseline levels (P < 0.005). With respect to patients with normal glucose tolerance (NGT), patients with impaired glucose tolerance (IGT) had higher baseline levels of isoleucine (78 ± 16 versus 70 ± 13 µmol L-1 , P = 0.014) and valine (286 ± 36 versus 268 ± 41 µmol L-1 , P = 0.049), respectively. Changes in levels of leucine and isoleucine after treatment were related negatively to changes in fasting plasma glucose and glycosylated haemoglobin values only in the conservative group (P < 0.05). In summary, we found that the treatment with CPAP for 12 weeks caused similar changes in circulating BCAAs concentrations to conservative treatment and a differential metabolic response of CPAP and conservative treatment was observed between the relationship of BCAAs and glucose homeostasis. Additional studies are needed to determine the interplay between branched-chain amino acids and glucose metabolism in patients with sleep apnea.

Obstructive sleep apnoea in the elderly: role of continuous positive airway pressure treatment.

Almost all the information about the effect of continuous positive airway pressure (CPAP) in patients with obstructive sleep apnoea (OSA) comes from clinical trials involving only middle-aged patients. The objective of this study was to assess the effect of CPAP treatment in elderly patients with severe OSA on clinical, quality-of-life and neurocognitive spheres. We performed an open-label, randomised, multicentre clinical trial in a consecutive clinical cohort of 224 elderly (≥70 years old) patients with confirmed severe OSA (apnoea-hypopnea index ≥30) randomised to receive CPAP (n=115) or no CPAP (n=109) for 3 months. A sleep study was performed by either full polysomnography or respiratory polygraphy. CPAP titration was performed by an autoCPAP device. The primary endpoint was quality of life (Quebec Sleep Questionnaire) and secondary endpoints included sleep-related symptoms, presence of anxiety/depression, office-based blood pressure and some neurocognitive tests. The mean±sd age was 75.5±3.9 years. The CPAP group achieved a greater improvement in all quality-of-life domains (p<0.001; effect size: 0.41-0.98), sleep-related symptoms (p<0.001; effect size 0.31-0.91) as well as anxiety (p=0.016; effect size 0.51) and depression (p<0.001; effect size: 0.28) indexes and some neurocognitive tests (digit symbol test (p=0.047; effect size: 0.20) and Trail Making Test A (p=0.029; effect size: 0.44)) in an intention-to-treat analysis. In conclusion, CPAP treatment resulted in an improvement in quality of life, sleep-related symptoms, anxiety and depression indexes and some neurocognitive aspects in elderly people with severe OSA.

Continuous positive airway pressure in clinically stable patients with mild-to-moderate obesity hypoventilation syndrome and obstructive sleep apnoea.

BACKGROUND AND OBJECTIVE: The use of continuous positive airway pressure (CPAP) treatment in patients with obesity hypoventilation syndrome (OHS) and obstructive sleep apnoea (OSA) was evaluated, and factors that might predict CPAP treatment failure were determined. METHODS: A sleep study was performed in 29 newly diagnosed, clinically stable OHS patients. CPAP treatment was commenced if the apnoea-hypopnoea index was >15. Lung function, night-time oximetry, blood adipokine and C-reactive protein levels were assessed prospectively on enrollment and after 3 months. Treatment failure at 3 months was defined as daytime arterial partial pressure of carbon dioxide (PaCO(2)) >45 mm Hg and/or oxygen saturation (SpO(2)) <90% for >30% of the night-time oximetry study. RESULTS: All patients had severe OSA (median apnoea-hypopnoea index = 74.7 (62-100) with a nocturnal mean SpO(2) of 81.4 ± 7), and all patients were treated with CPAP. The percentage of time spent below 90% saturation improved from 8.4% (0.0-39.0%) to 0.3% (0.4-4.0%). Awake PaCO(2) decreased from 50 (47-53) mm Hg to 43 (40-45) mm Hg. Seven patients failed CPAP treatment after 3 months. PaCO(2) at 1 month and mean night-time SpO(2) during the first night of optimal CPAP were associated with treatment failure at 3 months (odds ratio 1.4 (1.03-1.98); P = 0.034 and 0.6 (0.34-0.93); P = 0.027). CONCLUSIONS: CPAP treatment improves night-time oxygenation and daytime hypoventilation in selected clinically stable OHS patients who also have OSA. Patients with worse night-time saturation while on CPAP and higher daytime PaCO(2) at 1 month were more likely to fail CPAP treatment.

How does obstructive sleep apnea alter cerebral hemodynamics?

STUDY OBJECTIVES: We aimed to characterize the cerebral hemodynamic response to obstructive sleep apnea/hypopnea events, and evaluate their association to polysomnographic parameters. The characterization of the cerebral hemodynamics in obstructive sleep apnea (OSA) may add complementary information to further the understanding of the severity of the syndrome beyond the conventional polysomnography. METHODS: Severe OSA patients were studied during night sleep while monitored by polysomnography. Transcranial, bed-side diffuse correlation spectroscopy (DCS) and frequency-domain near-infrared diffuse correlation spectroscopy (NIRS-DOS) were used to follow microvascular cerebral hemodynamics in the frontal lobes of the cerebral cortex. Changes in cerebral blood flow (CBF), total hemoglobin concentration (THC), and cerebral blood oxygen saturation (StO2) were analyzed. RESULTS: We considered 3283 obstructive apnea/hypopnea events from sixteen OSA patients (Age (median, interquartile range) 57 (52-64.5); females 25%; AHI (apnea-hypopnea index) 84.4 (76.1-93.7)). A biphasic response (maximum/minimum followed by a minimum/maximum) was observed for each cerebral hemodynamic variable (CBF, THC, StO2), heart rate and peripheral arterial oxygen saturation (SpO2). Changes of the StO2 followed the dynamics of the SpO2, and were out of phase from the THC and CBF. Longer events were associated with larger CBF changes, faster responses and slower recoveries. Moreover, the extrema of the response to obstructive hypopneas were lower compared to apneas (p < .001). CONCLUSIONS: Obstructive apneas/hypopneas cause profound, periodic changes in cerebral hemodynamics, including periods of hyper- and hypo-perfusion and intermittent cerebral hypoxia. The duration of the events is a strong determinant of the cerebral hemodynamic response, which is more pronounced in apnea than hypopnea events.

Role of Sleep Apnea and Long-Term CPAP Treatment in the Prognosis of Patients With Melanoma: A Prospective Multicenter Study of 443 Patients.

BACKGROUND: OSA has been associated with increased incidence and aggressiveness of melanoma. However, the long-term impact of OSA and CPAP treatment on the prognosis of melanoma remains unexplored. RESEARCH QUESTION: Are OSA and CPAP treatment associated independently with a poor prognosis for cutaneous melanoma? STUDY DESIGN AND METHODS: Four hundred forty-three patients with a diagnosis of cutaneous melanoma (2012-2015) underwent a sleep study within 6 months of diagnosis. The main 5-year outcome of the study was a composite of melanoma recurrence, metastasis, or mortality. Patients were divided into four groups: baseline apnea-hypopnea index (AHI) of fewer than 10 events/h (no OSA; control group), OSA treated with CPAP and good adherence, untreated or poor CPAP adherence in moderate (AHI, 10-29 events/h), and severe OSA (AHI, ≥ 30 events/h). Survival analysis was used to determine the independent role of OSA and CPAP treatment on melanoma composite outcome. RESULTS: Three hundred ninety-one patients (88.2%) were available for analysis at 5-year follow-up (mean age, 65.1 ± 15.2 years; 49% male; Breslow index, 1.7 ± 2.5 mm). One hundred thirty-nine patients had AHI of fewer than 10 events/h (control group); 78 patients with OSA were adherent to CPAP; and 124 and 50 patients had moderate and severe OSA, respectively, without CPAP treatment. Median follow-up was 60 months (interquartile range, 51-74 months). During follow-up, 32 relapses, 53 metastases, and 52 deaths occurred (116 patients showed at least one of the main composite outcomes). After adjusting for age, sex, sentinel lymph nodes affected at diagnosis, BMI, diabetes, nighttime with an oxygen saturation below 90%, Breslow index, Epworth sleepiness scale scores, and melanoma treatment, moderate (hazard ratio [HR], 2.45; 95% CI, 1.09-5.49) and severe OSA (HR, 2.96; 95% CI, 1.36-6.42) were associated with poorer prognosis of melanoma compared with the control group. However, good adherence to CPAP avoided this excess risk (HR, 1.66; 95% CI, 0.71-3.90). INTERPRETATION: Moderate to severe untreated OSA is an independent risk factor for poor prognosis of melanoma. Treatment with CPAP is associated with improved melanoma outcomes compared with untreated moderate to severe OSA.

Effect of continuous positive airway pressure on the incidence of hypertension and cardiovascular events in nonsleepy patients with obstructive sleep apnea: a randomized controlled trial.

CONTEXT: Continuous positive airway pressure (CPAP) is the first-line treatment for patients with symptomatic obstructive sleep apnea (OSA). However, its indication for all patients with sleep-disordered breathing, regardless of daytime symptoms, is unclear. OBJECTIVE: To evaluate the effect of CPAP treatment on the incidence of hypertension or cardiovascular events in a cohort of nonsleepy patients with OSA. DESIGN, SETTING, AND PATIENTS: Multicenter, parallel-group, randomized controlled trial in 14 teaching hospitals in Spain. Between May 2004 and May 2006, 725 consecutive patients were enrolled who had an apnea-hypopnea index of 20 h(-1) or greater and an Epworth Sleepiness Scale score of 10 or less (scores range from 0-24, with values <10 suggesting no daytime sleepiness). Exclusion criteria were previous cardiovascular event, physical or psychological incapacity, chronic disease, or drug or alcohol addiction. Follow-up ended in May 2009. INTERVENTION: Patients were allocated to receive CPAP treatment or no active intervention. All participants received dietary counseling and sleep hygiene advice. MAIN OUTCOME MEASURES: Incidence of either systemic hypertension (taking antihypertensive medication or blood pressure greater than 140/90 mm Hg) or cardiovascular event (nonfatal myocardial infarction, nonfatal stroke, transient ischemic attack, hospitalization for unstable angina or arrhythmia, heart failure, or cardiovascular death). RESULTS: Seven hundred twenty-three patients underwent follow-up for a median of 4 (interquartile range, 2.7-4.4) years (1 patient from each group did not receive allocated treatment); 357 in the CPAP group and 366 in the control group were included in the analysis. In the CPAP group there were 68 patients with new hypertension and 28 cardiovascular events (17 unstable angina or arrhythmia, 3 nonfatal stroke, 3 heart failure, 2 nonfatal myocardial infarction, 2 transient ischemic attack, 1 cardiovascular death). In the control group there were 79 patients with new hypertension and 31 cardiovascular events (11 unstable angina or arrhythmia, 8 nonfatal myocardial infarction, 5 transient ischemic attack, 5 heart failure, 2 nonfatal stroke). The hypertension or cardiovascular event incidence density rate was 9.20 per 100 person-years (95% CI, 7.36-11.04) in the CPAP group and 11.02 per 100 person-years (95% CI, 8.96-13.08) in the control group. The incidence density ratio was 0.83 (95% CI, 0.63-1.1; P = .20). CONCLUSIONS: In patients with OSA without daytime sleepiness, the prescription of CPAP compared with usual care did not result in a statistically significant reduction in the incidence of hypertension or cardiovascular events. However, the study may have had limited power to detect a significant difference. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00127348.

Feasibility and Long-Term Compliance to Continuous Positive Airway Pressure Treatment in Adults With Down Syndrome, a Genetic Form of Alzheimer's Disease.

Background: Down syndrome (DS) is a genetic form of Alzheimer's disease (AD) with a high prevalence of obstructive sleep apnea (OSA). These characteristics place the DS population as an optimal model to study the relationship between sleep and AD and to design clinical trials of preventive sleep therapies for AD. Regrettably, OSA treatment with continuous positive airway pressure (CPAP) is often neglected in adults with DS. In both clinical practice and research trials, it is usually presumed that these patients will not adapt to or tolerate the therapy. Study Objective: We aimed to evaluate the feasibility and long-term CPAP compliance in this population and their capacity to be enrolled in CPAP research studies. Methods: We prospectively compared the CPAP compliance of 17 OSA patients with DS and 19 age and sex matched OSA euploid patients. CPAP management and follow-up schedules were prescribed according to the habitual clinical practice. We compared group differences in tolerance, objective, and subjective hours of nightly CPAP usage at the 1st, 3rd, 6th, 12th, 24th, and 36th month visits. Good compliance was defined as at least 4 h use per night. We also investigated predictive factors of long-term CPAP compliance. Results: The percentage of DS subjects with good CPAP compliance (81.2 vs. 78.9%) and the objective CPAP use (5 vs. 6 h, p = 0.92) did not differ from the control group (CG). Subjective CPAP compliance was significantly higher in OSA patients with DS than in controls in all the follow-up visits (8 vs. 6.75 h, p = 0.001). The DS group had a significantly higher number of visits (9 vs. 5; p = 0.021) and mask changes (2.5 vs. 2; p = 0.05) than controls. Objective hours of CPAP use at the first follow-up visit predicted long-term CPAP compliance (p < 0.005). Conclusion: CPAP treatment is feasible and has good long-term compliance in OSA patients with DS. It should be recommended to improve health and prevent comorbidities. The DS population is indeed suitable to participate in longitudinal preventive sleep clinical trials for AD.

Predicting nocturnal hypoventilation in hypercapnic chronic obstructive pulmonary disease patients undergoing long-term oxygen therapy.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients are very sensitive to changes in pulmonary mechanics and central ventilation control during sleep and may develop significant gas exchange alterations with increased hypoxemia and hypercapnia. Oxygen therapy improves nocturnal desaturation but can worsen hypoventilation. OBJECTIVES: To analyze the prevalence of nocturnal hypoventilation (NHV) in hypercapnic COPD patients and to determine predictive factors for this phenomenon. METHODS: This was a prospective multicenter study which enrolled 80 clinically stable COPD patients with hypercapnic respiratory failure who fulfilled the conventional criteria for long-term oxygen therapy (LTOT). All patients had undergone pulmonary function testing, blood gas analysis, and respiratory polygraphy. Arterial blood gas samples were obtained while patients were awake and during sleep. NHV was considered when an increase in PaCO2 >10 mm Hg was observed in any nocturnal arterial blood gas sample as compared to the awake levels. RESULTS: Seventeen patients (21%) developed NHV. NHV was associated with the values of BMI, hemoglobin, hematocrits, DLCO, and PaO2 reached after oxygen administration. In the logistic regression analysis BMI (OR 1.26, 95% CI 1.068-1.481; p = 0.006) and the diurnal increase of PaO2 after O2 (OR 0.89, 95% CI 0.807-0.972; p = 0.010) were the variables that best discriminated with a sensitivity of 82% and a specificity of 78%. CONCLUSIONS: NHV is a relatively common finding in stable hypercapnic COPD patients undergoing LTOT and it is related to a higher BMI and lower PaO2 after oxygen administration.

Long-term effect of continuous positive airway pressure in hypertensive patients with sleep apnea.

RATIONALE: Continuous positive airway pressure (CPAP) is the current treatment for patients with symptomatic obstructive sleep apnea (OSA). Its use for all subjects with sleep-disordered breathing, regardless of daytime symptoms, is unclear. OBJECTIVES: This multicenter controlled trial assesses the effects of 1 year of CPAP treatment on blood pressure (BP) in nonsymptomatic, hypertensive patients with OSA. METHODS: We evaluated 359 patients with OSA. Inclusion criteria consisted of an apnea-hypopnea index (AHI) greater than 19 hour(-1), an Epworth Sleepiness Scale score less than 11, and one of the following: under antihypertensive treatment or systolic blood pressure greater than 140 or diastolic blood pressure greater than 90 mm Hg. Patients were randomized to CPAP (n = 178) or to conservative treatment (n = 181). BP was evaluated at baseline and at 3, 6, and 12 months of follow-up. MEASUREMENTS AND MAIN RESULTS: Mean (SD) values were as follows: age, 56 +/- 10 years; body mass index (BMI), 32 +/- 5 kg x m(-2); AHI, 45 +/- 20 hour(-1); and Epworth Sleepiness Scale score, 7 +/- 3. After adjusting for follow-up time, baseline blood pressure values, AHI, time with arterial oxygen saturation less than 90%, and BMI, together with the change in BMI at follow-up, CPAP treatment decreased systolic blood pressure by 1.89 mm Hg (95% confidence interval: -3.90, 0.11 mm Hg; P = 0.0654), and diastolic blood pressure by 2.19 mm Hg (95% confidence interval: -3.46, -0.93 mm Hg; P = 0.0008). The most significant reduction in BP was in patients who used CPAP for more than 5.6 hours per night. CPAP compliance was related to AHI and the decrease in Epworth Sleepiness Scale score. CONCLUSIONS: In nonsleepy hypertensive patients with OSA, CPAP treatment for 1 year is associated with a small decrease in BP. This effect is evident only in patients who use CPAP for more than 5.6 hours per night. Clinical trial registered with www.clinicaltrials.gov (NCT00127348).

Visual analogical well-being scale for sleep apnea patients: validity and responsiveness : a test for clinical practice.

INTRODUCTION: Health-related quality-of-life (HRQL) tests used in sleep apnea-hypopnea syndrome (SAHS) are time-consuming, complicating their application in clinical practice. The objective was to examine the validity and responsiveness of a simple visual analogical well-being scale (VAWS) for the clinical use. METHOD: The subjects proceed from a cohort of SAHS patients treated with CPAP for 12 weeks. We correlated the VAWS with other HRQL tests, related clinical and polysomnographic measures to concurrent and construct validities. Responsiveness by: (1) comparison of HRQL tests between before and after treatment and effect size. (2) Association of the change with treatment between VAWS with other HRQL tests and between VAWS with clinical parameters. RESULTS: At baseline, VAWS correlated with all HRQL tests but better with functional outcomes in sleep questionnaires (FOSQ) and European quality-of-life questionnaire (EuroQol) thermometer. VAWS and FOSQ correlated better with clinical variables than other HRQL tests. VAWS captures the magnitude change with treatment similarly to FOSQ but better than other HRQL tests. CONCLUSION: VAWS is a very simple test which measures HRQL in SAHS. It could be a useful tool in clinical practice, primarily for the responsiveness of treatment.

Correlation Between Respiratory Accessory Muscles and Diaphragm Pillars MRI and Pulmonary Function Test in Late-Onset Pompe Disease Patients.

Objectives: Pompe disease is a rare genetic disease produced by mutations in the GAA gene leading to progressive skeletal and respiratory muscle weakness. T1-weighted magnetic resonance imaging is useful to identify fatty replacement in skeletal muscles of late-onset Pompe disease (LOPD) patients. Previous studies have shown that replacement by fat correlates with worse results of muscle function tests. Our aim was to investigate if fat replacement of muscles involved in the ventilation process correlated with results of the spirometry and predicted respiratory muscle impairment in LOPD patients over time. Materials and Methods: We studied a cohort of 36 LOPD patients followed up annually in our center for a period of 4 years. We quantified muscle fat replacement using Mercuri score of the thoracic paraspinal and abdominal muscles and the pillars of the diaphragm. We correlated the combined Mercuri scores of these areas with spirometry results and the need of respiratory support. Results: We found a statistically significant correlation (Spearman test, p < 0.05; coefficient of correlation > 0.6) between forced vital capacity seated and lying and fat fraction score of all muscle groups studied. The group of patients who needed respiratory support had higher fat fraction scores than patients not requiring ventilatory support. Higher fat replacement in these areas correlated with worse progression in spirometry values over time. Conclusions: Fat replacement of paraspinal, abdominal, and trunk muscles correlates with results of spirometry and is able to predict worsening in respiratory muscle function tests that could lead to an emerging ventilatory dysfunction. Therefore, the identification of fat replacement in these muscle groups should lead to a closer monitorization of patients. Radiologic evaluation of diaphragm pillars in T1-weighted imaging axial sequences could also be helpful to predict respiratory insufficiency.

Sleep hypoventilation due to increased nocturnal oxygen flow in hypercapnic COPD patients.

UNLABELLED: This study shows the risks and benefits of increasing the nocturnal oxygen flow in hypercapnic COPD patients undergoing LTOT, as recommended by some COPD treatment guidelines to avoid nocturnal desaturation. BACKGROUND AND OBJECTIVE: Several COPD treatment guidelines recommend increasing oxygen flow during sleep to avoid nocturnal desaturation. However, such an increase could have deleterious clinical and gas exchange effects. The objective of this study was to evaluate short-term gas exchange alterations produced by increasing the nocturnal oxygen flow rate. METHODS: Thirty-eight COPD patients with chronic hypercapnic respiratory failure were evaluated. In a cross-over study, patients were randomly assigned to receive the daytime oxygen flow rate on one night and an additional litre on the alternate night. Nocturnal pulse oximetry and arterial blood gases at awakening were measured, in each patient, on two consecutive days. RESULTS: The administration of 1 L more oxygen during the night resulted in improved parameters of nocturnal oxygenation (oxygen pulse oximetry saturation-SpO2; percentage of sleep time spent at SpO2<90%-CT90; PaO2 at awakening). Nevertheless, such an increase in oxygen flow during the night was also associated with greater hypercapnia and acidosis (p<0.05) the next morning. CONCLUSIONS: The increase of oxygen flow in severe COPD patients with established daytime hypercapnia improved nocturnal oxygenation but it also led to greater hypercapnia and respiratory acidosis at awakening in a considerable proportion of these patients.

Respiratory sleep disturbances in patients undergoing gastric bypass surgery and their relation to metabolic syndrome.

BACKGROUND: The prevalence of obstructive sleep apnea syndrome (OSAS) is high in obese patients. Certain components of metabolic syndrome are linked to OSAS, but there is no information on their association in morbidly obese patients. Our aim was to ascertain the prevalence of respiratory disturbances during sleep in candidates for bariatric surgery and to study their association with metabolic syndrome. METHODS: We examined the preoperative records (history, physical examination and laboratory findings, spirometry, and overnight pulse oximetry [arterial oxygen saturation by pulse oximetry, [SpO(2)]]) of patients scheduled for gastric bypass surgery for 1 year in our hospital; an overnight sleep study was performed if SpO(2) readings or symptoms suggested sleep disturbance. Metabolic syndrome was defined according to the criteria of the National Cholesterol Education Program's Adult Treatment Panel III. RESULTS: Of the 31 patients studied, 19 (61.3%) had OSAS, including 15 newly diagnosed cases with a mean +/- standard deviation apnea-hypopnea index of 49 +/- 36. OSAS patients had higher fasting plasma glucose and triglyceride levels and a higher prevalence of diabetes. Metabolic syndrome was also more frequent in subjects with previously untreated OSAS (13/14, 92%) than in those without sleep disturbance (six of 11, 55%; p = 0.033). Conversely, the prevalence of OSAS in patients with metabolic syndrome was higher (13/19, 68%) than in subjects without metabolic syndrome (one of six, 17%; p = 0.026) even though the two groups had similar body mass index. CONCLUSIONS: Sleep disordered breathing is very prevalent in obese patients who are candidates for bariatric surgery and its presence is related to metabolic syndrome.

Microvascular cerebral blood flow fluctuations in association with apneas and hypopneas in acute ischemic stroke.

In a pilot study on acute ischemic stroke (AIS) patients, unexpected periodic fluctuations in microvascular cerebral blood flow (CBF) had been observed. Motivated by the relative lack of information about the impact of the emergence of breathing disorders in association with stroke on cerebral hemodynamics, we hypothesized that these fluctuations are due to apneic and hypopneic events. A total of 28 patients were screened within the first week after stroke with a pulse oximeter. Five (18%) showed fluctuations of arterial blood oxygen saturation ( ≥ 3 % ) and were included in the study. Near-infrared diffuse correlation spectroscopy (DCS) was utilized bilaterally to measure the frontal lobe CBF alongside respiratory polygraphy. Biphasic CBF fluctuations were observed with a bilateral increase of 27.1 % ± 17.7 % and 29.0 % ± 17.4 % for the ipsilesional and contralesional hemispheres, respectively, and a decrease of - 19.3 % ± 9.1 % and - 21.0 % ± 8.9 % for the ipsilesional and contralesional hemispheres, respectively. The polygraph revealed that, in general, the fluctuations were associated with apneic and hypopneic events. This study motivates us to investigate whether the impact of altered respiratory patterns on cerebral hemodynamics can be detrimental in AIS patients.

PDGF-BB serum levels are decreased in adult onset Pompe patients.

Adult onset Pompe disease is a genetic disorder characterized by slowly progressive skeletal and respiratory muscle weakness. Symptomatic patients are treated with enzymatic replacement therapy with human recombinant alfa glucosidase. Motor functional tests and spirometry are commonly used to follow patients up. However, a serological biomarker that correlates with the progression of the disease could improve follow-up. We studied serum concentrations of TGFß, PDGF-BB, PDGF-AA and CTGF growth factors in 37 adult onset Pompe patients and 45 controls. Moreover, all patients performed several muscle function tests, conventional spirometry, and quantitative muscle MRI using 3-point Dixon. We observed a statistically significant change in the serum concentration of each growth factor in patients compared to controls. However, only PDGF-BB levels were able to differentiate between asymptomatic and symptomatic patients, suggesting its potential role in the follow-up of asymptomatic patients. Moreover, our results point to a dysregulation of muscle regeneration as an additional pathomechanism of Pompe disease.

Cerebral vasoreactivity in response to a head-of-bed position change is altered in patients with moderate and severe obstructive sleep apnea.

MOTIVATION: Obstructive sleep apnea (OSA) can impair cerebral vasoreactivity and is associated with an increased risk of cerebrovascular disease. Unfortunately, an easy-to-use, non-invasive, portable monitor of cerebral vasoreactivity does not exist. Therefore, we have evaluated the use of near-infrared diffuse correlation spectroscopy to measure the microvascular cerebral blood flow (CBF) response to a mild head-of-bed position change as a biomarker for the evaluation of cerebral vasoreactivity alteration due to chronic OSA. Furthermore, we have monitored the effect of two years of continuous positive airway pressure (CPAP) treatment on the cerebral vasoreactivity. METHODOLOGY: CBF was measured at different head-of-bed position changes (supine to 30° to supine) in sixty-eight patients with OSA grouped according to severity (forty moderate to severe, twenty-eight mild) and in fourteen control subjects without OSA. A subgroup (n = 13) with severe OSA was measured again after two years of CPAP treatment. RESULTS: All patients and controls showed a similar CBF response after changing position from supine to 30° (p = 0.819), with a median (confidence interval) change of -17.5 (-10.3, -22.9)%. However, when being tilted back to the supine position, while the control group (p = 0.091) and the mild patients with OSA (p = 0.227) recovered to the initial baseline, patients with moderate and severe OSA did not recover to the baseline (9.8 (0.8, 12.9)%, p < 0.001) suggesting altered cerebral vasoreactivity. This alteration was correlated with OSA severity defined by the apnea-hypopnea index, and with mean nocturnal arterial oxygen saturation. The CBF response was normalized after two years of CPAP treatment upon follow-up measurements. CONCLUSION: In conclusion, microvascular CBF response to a head-of-bed challenge measured by diffuse correlation spectroscopy suggests that moderate and severe patients with OSA have altered cerebral vasoreactivity related to OSA severity. This may normalize after two years of CPAP treatment.